Quark QP2A-X or QP2L-X - playing mix and match with tubes and batteries

Hi everyone,

I'm looking for my first "real" light and I find the specs and lego ability of the foursevens lights to be appealing. I'm looking for a general use/everyday light. I would like decent output on the highest mode, but I don't necessarily need 700-800 lumens (I don't think......but it would be fun ). I would like to get as long of run time as possible, but also want the ability to use regular old AA alkaline batteries as well so I can just stop at a gas station in the boondocks and still use my light. That being said, I'm also interested in getting another tube or two to have more power options when I'm closer to home.

I'm primarily debating between the QP2A-X and QP2L-X, both of which seem like great bases for modification. Obviously the main difference is the voltage of the heads (0.9-4.2 for the 2A-X, 3-9 for the 2L-X). So, questions:

1. if I went with the high voltage head, would a single RCR123 or 14500 or 2 alkaline AAs sufficiently power it? I presume it would lower the output, but is there a way to estimate how much?What would the run time be like?
2. can you use a 17670 in a L2 tube with the low voltage head (the AW 17670 says 3.7V)? I presume it would be similar to the QPL as far as output, but with longer run time?

Based on my current understanding of the lights and batteries I'm leaning toward the low voltage head and getting a A and 2L bodies so I can run a 14500 to make it a shorty with good output, or use a 17670 in the 2L body for longest run time, and still have the 2A so I can run whatever AA batteries I can find.

Thanks.

ajssbp said:

Hi everyone,

I'm looking for my first "real" light and I find the specs and lego ability of the foursevens lights to be appealing. I'm looking for a general use/everyday light. I would like decent output on the highest mode, but I don't necessarily need 700-800 lumens (I don't think......but it would be fun ). I would like to get as long of run time as possible, but also want the ability to use regular old AA alkaline batteries as well so I can just stop at a gas station in the boondocks and still use my light. That being said, I'm also interested in getting another tube or two to have more power options when I'm closer to home.

I'm primarily debating between the QP2A-X and QP2L-X, both of which seem like great bases for modification. Obviously the main difference is the voltage of the heads (0.9-4.2 for the 2A-X, 3-9 for the 2L-X). So, questions:

1. if I went with the high voltage head, would a single RCR123 or 14500 or 2 alkaline AAs sufficiently power it? I presume it would lower the output, but is there a way to estimate how much?What would the run time be like?
2. can you use a 17670 in a L2 tube with the low voltage head (the AW 17670 says 3.7V)? I presume it would be similar to the QPL as far as output, but with longer run time?

Based on my current understanding of the lights and batteries I'm leaning toward the low voltage head and getting a A and 2L bodies so I can run a 14500 to make it a shorty with good output, or use a 17670 in the 2L body for longest run time, and still have the 2A so I can run whatever AA batteries I can find.

Thanks.

Click to expand...

1. Yes, a single RCR123 (16340) and 14500 will power the high voltage head, but better to run an IMR cell than ICR as it's rated for the heavy ~2 amp draw of the burst mode... you generally should not exceed 2C with a IMR, but people use it too. Search for ti-force's review of this light... a 14500 will power it up to 750 lms and he has output runtime graphs with the various cells.

The light will limp on 2AAs... IIRC, you won't get burst mode but you'll get high, or some level high, and the rest of the lower modes. The light will run on <2.5V (2x dying Eneloops) on moonlight and low.

2. Yes, the low voltage head runs fine on a 17670, but the Sanyo 16650 cell might have more capacity, so consider that as well, and they should the longest runtime of rechargeables.... I think 2 lithium primary L91s would run longer though. The QP2A-X head will be brighter and floodier than that QPL since that light uses the XPG2.

I have nearly all of the Quark heads and Lego parts, and if I had to drop it down to one set-up, it would be the QP2A-X with 1AA tube and deep pocket carry clip. I do run a 17670 sometimes as well, but as a low-lumen/night-vision/runtime enthusiast, a single 14500 lasts me forever. For me, the emergency ability to efficiently run any cell (9V, AAA, AA and anything between CR123 and 18650 with a piece of MacGyver tinfoil) far exceeds double the output (800 vs 400 lms) of the high voltage head. But the HV head does make a seriously fun show-off light . You also have to try the single-handed momentary-max from ON with the Pro UIs, it's my favorite UI "feature" of any light. My favorite light period .

First, thanks for the feedback reppans, I appreciate it.

Ok, so I've been doing more reading. I stumbled across a thread talking about using the 18650 with the quark heads and one of the things I took from the thread is if using any of the rechargeable LiIons (17670, 16650, or 18650) is that the lower voltage head (because it's both a buck/boost head) will basically run until the protection circuit kicks in and then the light cuts out. I know this probably isn't great for the batteries. So is this the case still (it was a 3-4 year old thread after all)? Assuming it is true, how do you know when to change the battery? I don't really want to check the voltage every few days.......

I keep going back and forth with what I think I am going to get.... I have this sinking feeling I'll wind up with both eventually.........

Dang it.

Yes, the LV head will run ICRs to the protection circuit tripping whereas I suppose the HV head would start stepping down in output, and perhaps shut-off, before the protection kicked in. Hasn't been an issue for me for a couple of reasons. Li-ions are probably the best of any battery chemistry for gauging remaining capacity from resting voltage, so after a few cycles of frequent voltage checks, I have a really good sense of how much juice I'm using - I now check voltage about 1/wk (~10-15 hrs of usage) and can "guess" where I am within +/- 0.05V. I like some emergency runtime and so typically recharge ~ 40% SoC, so I never really get close to the protection circuits tripping.